(Wikimedia Commons)

It appeared as though it was placed inside or under the building in a tunnel, according to the director of the night staff on watch. A rebel group has already claimed responsibility. They recorded and uploaded the attack to YouTube.

In the preceding weeks, the pro-Assad army has held camp in the north of Syria while the rebels attack with bombs and mortar strikes in government-held territory, including Damascus.

The government is mostly in control of Harasta, the suburb, but the rebels have been trying to gain a foothold there since last year.